


Sheen and Luster

by AyaKazumi



Series: Stars and Bones [2]
Category: Undertale (Video Game)
Genre: Cunnilingus, Ecto-Penis (Undertale), Ecto-Tongue (Undertale), F/M, Female Reader, Fluff and Smut, I suck at tags, My First Smut, Sans knows what to do, Smut, Somehow, Top Sans (Undertale), Vaginal Sex, at least I hope my writing isn't awkward, not awkward sex
Language: English
Status: Completed
Published: 2020-08-18
Updated: 2020-08-18
Packaged: 2021-03-05 20:07:07
Rating: Explicit
Warnings: Creator Chose Not To Use Archive Warnings
Chapters: 1
Words: 3,725
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/25951120
Author URL: https://archiveofourown.org/users/AyaKazumi/pseuds/AyaKazumi
Summary: Sans and you have some fun after getting horny while stargazing.(You don't need to read the first part to understand this one.)
Relationships: Sans (Undertale)/Reader
Series: Stars and Bones [2]
Series URL: https://archiveofourown.org/series/1883518
Kudos: 60





	Sheen and Luster

**Author's Note:**

> Picks up where I left off with the first part, you don't need to read the first part, this is all shameless smut.  
> This is my first time writing smut... At least I try, hah :'D

You pull Sans with you, barely noticing him closing your door before capturing him in a kiss once more. It has you addicted already, the feeling of his tongue dancing with yours, the pleasant jolts running through your whole being. You shiver when he runs his hands down your back and up again. Your own hands find the back of his neck, rather his vertebrae, and start to scritch there. The noise you earn for this has heat pooling in your abdomen.

When his fingers catch at the hem of your shirt, your breath hitches and you feel him grinning against you. The next time his hands reach the bottom of your shirt, he slips them underneath, starting to run his hands over the skin of your back. You can't help the mewl that escapes you at the contact and stumble back towards your bed.

Before you can trip, Sans steadies you and holds you close, never breaking the contact of your kiss. He pulls at your shirt and you reluctantly put some centimeters of distance between the two of you, to all but rip your shirt off, returning to what you were doing before eagerly.

Now unhindered, Sans' hands roam over your exposed upper body, exploring every little spot around your back, stomach, sides and shoulders. The traveling stops at the clasp of your bra. Through your lidded gaze you notice his brow furrowing, unable to stop a grin of your own. You feel him fumbling around with it for a moment before giving in. You break your contact for a moment "hooks on one side, loops on the other" you quickly explain before crashing back into him. Despite your vague declaration, he seems to get it because you can feel it coming undone a moment later.

You let go of his neck for a moment to slip out of the undergarment and return your hands to his shirt this time. You pull it upwards, prompting him to lift his arms away from your body for a moment. Exposed bones to your bare chest, you get tangled up in each other once more, finally toppling over onto your bed. With Sans straddling your lap you scoot further onto the mattress, having him lay down on top of you.

Your back now pressed into fabric, his hands quickly find your chest to keep busy. At first softly running his hands over the sensitive skin, he starts kneading your breasts carefully. His eyelights focused on your face, soaking up any and all reactions to his caressing, he leans in again, to capture your lips. Before he can close the distance fully, one of his joints brushes over your nipple, eliciting a soft moan that gets muffled by his tongue entering your mouth. He repeats the movement of his hand once or twice, getting it right the second time and finding the source of your pleasure, now deliberately rubbing over it with the tips of his phalanges.

The shivers return to your body, each shock of pleasure instantly revealed to Sans' observant eye. He keeps up the soft fondling for a bit longer, not breaking the kiss for even a second, and has you writhing underneath him before long. Soon enough, one of his hands starts trailing down, slightly ticklish at your side, and stops at your waistband. He breaks you two apart, supporting himself on his elbow while pulling your pants' waistband off your hip and letting it snap back into place quietly a few times. Getting the hint, you lift your hips off of the mattress, pulling the offending cloth down with Sans' help.

You accidentally also grabbed your panties and they go off along with your trousers, but you couldn't care less. Sans' hands are on you again, immediately after he'd shrugged his own pants off. Some might think it'd be unsettling seeing him bare like this, but Sans doesn't exactly look like a dead human skeleton, he's alive, and even though he shares some similarities with it, it's hardly a connection to be made. Aside from this, the glowing blue erection present at the base of his hipbone should get rid of all remaining doubts.

If anything, this revelation has you excited and impatient. 

He climbs back on top of you, leaning down to kiss you again, but he doesn't stay there. He nips small bites along your jawline, all the way to your ear, under which he leaves small licks. Leaning your head away from him, you grant him better access to your neck. An invitation he all too eagerly accepts, licking down your jugular and leaving little love-bites on the skin surrounding it.

Searching for something to hold onto, your hands finally find the front of Sans' rib-cage. Desperately clinging to two of them, you pull a harsh moan from him. You look at him surprised, finding a glowing blue blush on his face. One of his eyelights has almost completely disappeared, leaving the other one bigger and brighter, glowing a shade of blue and yellow. You keep your eyes on his remaining eyelight, experimentally rubbing along one of his ribs, trailing along its curve all the way to his spine. Judging by the shuddering breath that leaves him and the desperate thrust of his hips in the air, this is a good starting point to get him undone. You repeat the action with your other hand, this time having Sans moan out your name, letting his head fall back to your neck and biting down. 

You give a little squeak, he hadn't bitten you hard but it surprised you. He lets go again, only to lick at the spot in apology and nipping at your cheek before continuing his way down, along your neck, your shoulder, your collarbone, all the way to your breast. He eyes it for a moment before taking the nipple between his teeth carefully and licking at it. You shudder and shiver underneath him, breathing deeply to get enough oxygen into your system and fidgeting with your legs at the lack of stimulation there. Sitting on your thighs, Sans of course feels your restlessness.

He softly shushes you "calm down, we'll get there...", gives your nipple a small tug and lets it fall from between his teeth. He leans on his other arm, now focused on the second mound. He repeats the treatment he gave the first one, also moving his hand down to your hip, squeezing and kneading the flesh there, relishing in the feeling of skin on his bones. You moan out his name once more with one of the more powerful tremors, shaky voice and tensing thighs. He stops squeezing with his hand and instead lets it wander towards your center. 

He parts your tense legs with his knees, sitting between your thighs, never stopping his treatment on your chest. When his hand approaches your waiting sex, your legs part further on their own account. His fingers find your slit, rubbing across a few times and, as quickly as with your nipples, finds the spot that brings you the most pleasure. He uses three of his fingers to rub at your clitoris, the pinky and thumb holding his hand in place, simply for the fact that he can't hold the desperate movements of your hips down with just two fingers, so he goes along with the movement.

You lift your back off the mattress, pressing your front further into Sans, making him double his efforts. Making a noise in the back of your throat, you quietly beg for more, _different_ stimulation. Sans leaves your breast, lifting his head a bit to look you in the eye and shushes you gently once more "you're doing great, sweetie. we'll get there, let me have this..." 

Breathing heavily, you continue to hold his gaze, silently asking him to elaborate. He chuckles deeply "you don't know how long i've wanted this, i wanna savour it..." he finishes by leaning in and capturing you in a heated kiss once again, picking up his hands' movement again, making you moan into his mouth and arching up into him. When he breaks the kiss, you can't suppress a small whine, to which he winks at you and focuses back at you neck, leaving some nips and sloppy licks there, traveling downwards.

While keeping up his rhythmic hand-movements, his tongue reaches your chest again, caresses one of your nipples for a moment and continues its trek down your torso. He scooches back some more, ending up with his knees between your feet, hovering with his head above your center. He glances up to your face to look for any indication you might want to stop; not finding any hesitation, he leans down, slides his tongue out of his mouth and tries your sex.

You almost yell at the feeling of his magic at your most sensitive area, lifting your back off of the bed again in pleasure. Sans lays down between your legs and takes hold of your sides with both of his now-free hands, effectively holding you down. The room sways in front of your eyes and you close them to focus on what he's doing. 

Sans laps at your clitoris, swirling it in circles and slowly drags his tongue across it, feeling your shivers everywhere he's touching you. He lets his magic appendage drag down slowly, then back up, a little bit lower every time and finally finding your entrance. He swirls his tongue around it, going back up to your clitoris and down against your vagina once more. You can't hold in the yell that rips itself from your lungs when he thrusts it in, the magic having a weirdly cold-but-not feeling to it, prickling against your insides. He holds it still for a moment, glancing back up to make sure you're still okay, stroking gently at your sides to be soothing without tickling you. After you've taken a few deep breaths he pulls his tongue back out, licking at your clitoris again, then laying it flat against the length of your slit, pressing down. The tip of the appendage dips into your vagina again, all while the flat of it is still pressed up against your clitoris, slipping across to get more into you, bit by bit.

The breath that escapes you is a slow one, accompanied by a long, dragged-out moan of Sans' name. His thumbs caress your sides slowly while he continues to fill you up with his magic, making sure to drag across your bundle of nerves while doing it. When he feels a resistance against the tip of his tongue, he stops and holds it in place again. He'd read about it being painful to go further than this, so he slowly pulls out, still dragging over your nub with every motion. The muscles in your legs and back work to push you up off the bed again, but he holds you in place gently, if not pulling you into his face some more. 

When his tongue is almost all the way out of you, he pushes back in slowly, disregarding the nub a little to focus on the size of it, making it a little bit wider to fill you up more than last time. Your moans and gasps only encouraging him, he repeats this process a few times over, stretching you out little by little. He deems you stretched enough soon, focusing back on your clitoris and sending you back into almost yelling his name with the moans that get louder by the minute.

Focused on the bundle of nerves, he has you twitching and gyrating your hips into him fast. A few more big, slow laps of his literal magic tongue sends you over the edge, clamping your legs closed around his head. He keeps licking you all the way through it, until your legs start relaxing again. He laps up around your vagina, drinking up every last drop of your excitement. Noticing your blush at his actions, he deliberately licks over his teeth and crawls back up to you on all fours. 

He lowers his head to your neck, letting you catch your breath for a moment. He jolts at your hand on his erection. He glances at you from his space at your neck and sees you blush, so he holds still to let you go at your own pace. Your other hand finds his ribs, caressing each of them slowly, making him groan and involuntarily thrust his hips into your other hand. You press the second magic appendage softly, feeling it twitch in your grasp. Starting to slowly pump your hand on his penis, you keep your other hand moving slowly along each of his ribs, relishing in the little sounds he makes. When he notices your breathing evening out, he lifts his head and crashes his mouth to your lips, urgently pressing his tongue to yours.

Holding himself up with one of his hands to let you continue your movements, he lets the other one wander across your chest, caressing not only your breasts and nipples but everything his hand can reach, stopping on your cheek. He ends the kiss sweetly and looks you in the eye with a longing look you can feel resonate with your own feelings but can't put a word to. When your hand finds a particularly sensitive spot behind one of his ribs, he closes his eyes and outright _moans_ for you.

The noise shoots a jolt right between your legs, getting you bothered all over again, making you breathe out your own little noise for him. He opens his eyes again, looking at you with one light completely gone, the remaining light bright, eager.

He takes your wrists in his hands and pins them next to your head on each side, leaning down and kissing you deeply. When he lets go of your hands to caress your body once again, you wrap your arms around his neck, pulling him close. He lowers himself on top of you, laying down halfway and in the process pressing his hard-on against your thigh. An involuntary mewl leaves your throat at his arousal and he ruts against you once, mimicking your noise while doing so.

You wiggle your legs free from under him, not breaking the dance of your tongues, and wrap them around his hipbone. His penis now pressed on your pubic area, you gyrate your hips into him, using your legs wrapped around him as leverage, to get some sort of friction. He huffs a quiet chuckle at your eagerness, giving in and pulling his hips back enough to align his length with your entrance. Shoving his arms under your back, he grabs you by the shoulders from behind, holding you in place for what he's about to do.

Rubbing the head of his erection along your slit a few times, he slides right inside of you when pressing with a bit more purpose. You break your kiss to breathe in through your teeth, hissing in discomfort. Sans stops moving his hips, instead going to town on your neck, nibbling and licking there to distract you from the pain. You wiggle a bit when the feeling subsides, pulling him closer with your legs still wrapped around him. He pushes in slowly, being mindful of the very different feeling of his erect penis compared to his soft tongue.

The discomfort soon leaves your face as he hilts inside you. The magic feels different this time, rubbing in all the right places and by far not as wiggly as Sans' tongue. You thrust into him once you embraced the foreign feeling and can't suppress the loud moan that escapes you when he pulls out almost completely and pushes back in slowly but heavily. He captures you in a heated kiss again and repeats the motion, having you mewl into him, muffled by his tongue. 

He picks up the pace a bit, not stopping before pulling out and pushing back in, building up a steady, lazy rhythm. Sans continues tangling your tongues, now pulling on your shoulders, to reach even deeper inside you with each slow thrust of his hips. You meet him with every quiet noise his hips make on the flesh of your thighs, the bone digging into your skin, not painfully but noticeable enough to call back to your lust-hazed mind that this is Sans, and it's so much _him_ , your heart is overflowing with emotions.

His pace quickens slightly and the grip on your shoulders tightens when he breaks your kiss to lay his head in the crook of your neck, panting slightly. You let your arms fall from his neck to caress his ribs the way you did before, searching for that one spot that had him outright moaning. Your efforts are rewarded by his hips stuttering in their rhythm, but keeping their pace. Once you brush over a specific groove on the inside of one of his ribs, he slams into you with a loud moan of his own, basically curling in on himself with how desperately he's holding onto your shoulders, arching his back and in the process giving you better access to his ribs. You stroke over the spot you found more deliberately this time and he trembles with another moan before you feel his penis simply disappearing from within you, leaving you feeling empty.

He's panting heavily into your collarbone, leaning his forehead against your neck. You decide to not continue your stroking on his ribs and instead start scritching at his cervical vertebrae, hugging him loosely. Sans pulls his arms out from under your back, pushing his upper body off of you and searching your face. His eyelights are both there once more, no blue and yellow light in sight, looking into your eyes. When he opens his mouth to speak he's missing his tongue, all magic returned to his soul you assume.

"i love you" he says.

You stare at him, dumbfounded. When you don't answer immediately, he starts fidgeting. Once the words finally sunk in, properly registering in your head what he'd just declared, you fling your arms around his neck, pulling him back down to you and into a hot but sweet kiss. When you two finally break apart, he searches your face, this time from up close, and you can't help but chuckle.

"I love you, too." You peck a kiss to his cheek "You big lug."

He chuckles as well this time, nuzzling the ridge of his nose into your temple softly, sparking a bit of his magic at you and sending shivers across your skin again. A moment later, he pushes himself up once more, leaving you on your bed. He leaves the room, but returns a few minutes later with a towel and something to drink. He hands you the drink and motions for you to let him dry you off but you take the towel out of his grasp, cleaning up the mess you made yourself. "I can make a mess, I can clean it up" you mutter under your breath, eliciting a small laugh from Sans. 

You glance at him, "Don't laugh, I mean it. You did so much already, no need to also do this." You see him shrug out of the corner of your eye "wouldn't have done it if i didn't enjoy it" he says nonchalantly, making you blush darkly. "Don't say it like that!" you exclaim in a voice that's way too high to be normal. He chuckles again, sitting down next to you on the bed. You offer him the drink you sipped on, but he denies it "had something when i was in the kitchen. monster food i mean, gotta get some energy back..." he trails off and winks at you. 

When you finished cleaning yourself of sweat and other bodily fluids, you lay down with Sans on top of you again, lazily running your hands over his ribs and spine. Every time your finger catches a groove somewhere on his otherwise smooth bones, he shivers a little. His hands trail along your waist as well, soft enough to not scratch you with his bones but firm enough to not be ticklish. The two of you relish in each others' presence for some time before Sans' hand traces back to your neck, pulling you in for a long, slow kiss. His other hand finds your thigh, kneading at your skin firmly and you sigh into the kiss, leaning that leg out to give his hand better access, resulting in Sans slipping between your legs again.

He breaks the kiss and gives you a mischievous grin, dipping his head down to capture your nipple between his teeth. His tongue darts out to lick at it again, making you sigh and moan quietly. The hand on your thigh, agonizingly slowly, finds its way back to your center, starting to languidly trace over your slit and stopping to pay your clitoris some attention. Your breath hitches and you moan, rewarding Sans with the sounds he so desperately wants to hear.

Feeling you getting pretty wet way faster than the first time around, he leaves your breast to taste you once again. You can't help the noise that pulls itself free of your lungs at the sight of him slipping down to make you feel like you're in heaven a second time. When his tongue touches your clitoris, you thrust your hips down into his face desperately. He doesn't say anything at your needy action, only moving his hands to hold you down by your waist and leaning into your sex to use the flat of his tongue all over you.

Still being as aroused from the first time as you were, you become undone fast, moaning and calling Sans' name like a mantra before clamping your legs closed around his head. He guides you through your orgasm, never easing his pressure or his licks until you finally come down from your high, relaxing your legs.

With heavy breaths you glance down at him, noticing a glow from below his rib-cage. "When do you think we're done?" you ask through your gasps. Sans crawls up to you, tangling your tongues for a few long moments before answering;

"oh, we have the whole night, sweetheart..."


End file.
